Sick or Just Sleeping and Discolored

[HappySnapper]

My new betta, Sartorius was just transferred from a bowl to a 2 gallon tank with a filter. No heater...2 gallons is supposed to be too small for a heater to properly regulate. The only issue I've had in the tank (I put 3 neon tetra and 1 corey catfish) was a major ph change went from 7.2 to 6.0 in an hour and all the fish died except Sartorius, he seemed fine. I've got the water under control mostly (with bottled distilled water and ammonia's fine and pH is just slightly high. I also put 3 more fish in with him, all of whom seem fine. Lately though, he seems to be hanging out by the top in the dark corner, he still comes out to eat but doesn't swim around the puff as much. Now I mostly see him in the evening so I don't know if he's just widing down but he has some silver coloring on his face and I can't seem to remember if it was there that much before or if it's increased. (aka is it just his coloring or is he getting a fungus). Also if he has a fungus should I treat the whole tank? And will it hurt to treat just in case it's a fungus? I'm going to try this whole include pictures thing.

[Tinthalas Tigris]

how did the pH jump so wildly? Did you add some chemical to the water?

No pH change should ever change so quickly or drastically. Even a matter of 4 points too quickly will kill just about any fish, let alone 12 points. That is way too extreme of a change in an hour.

Those white patches aren't necessarily a disease, but they are definitely showing you that he is sick. You need to get him in somewhere with a better regulation of water conditions.

There are too many factors here at once. Switch to conditioned tap water, condition him to it slowly (in a cup), add 1 teaspoon of salt per gallon, and keep his termperature at 80 degrees.

Why again did the pH change so drastically?

[HappySnapper]

the problem in my house is the tap water. i live in a town with a well so i originally started with tap water conditioned with api conditioner. but unfortuantely it was impossible to control the water any better than that and I tested the pH of our tap water after conditioning and it was crazy high. Off the test reading chart. So i added the tiniest drops of pH correcter at a time and left it alone. Then A water change was made by my parents while I was at work (I work 12 hr night shifts) and I found the rest dead when I tried to figure out what had happened I found the pH was crazy. Again ammonia has remained stable I constantly check that and make necessary water changes. So I basically got rid of about 95% of the tap water and filled with distilled which tests pH wise normally. I have had a betta before who lived 3 years in a bowl. So this whole checking and controlling is new. Where else would I put him to better regulate? Besides checking the pH and the ammonia what else? Also is 2G too small for a heater or should I get one?

also i'm thinking partial water change? but i'm terrified to mess with my pH again after the last incident...I don't know that he could survive another apocolypse as I've been calling it.

also to recap i am worried about the 3 other fish as well :( i'm very paranoid about losing anymore fishies :(

ok i promise i won't assault you people with anymore information haha but i just rechecked my levels and ammonia remains about 0 and pH is about 6.4.

[Tinthalas Tigris]

Bettas can live in a wide range of pH, and tap water, because we consume it, is ussually the best to go with, as long as you are able to drink it healthily.

what is the pH of your tap water out of tap?

[xxabc]

Distilled does nothing good for your betta. If I were you, I'd go with "off-the-chart pH" rather then "lack-of-minerals" distilled. But what was the exact number of pH?

I have a betta with those exact colors. He gets those colors when he 1) Just woke up (I'm being serious haha) or 2) got too cold (forgot to plug heater in).

Wait, you added more fish into a 2 gallon? Bad move - bettas should be very alone given the exception of some shrimp or one snail at the most. Keep up with your water changes.

Lots of plants gives sense of security to your bettas. Try adding more plants.